//调用门元件实现的4选1 MUX
module mux4_1a(out,in1,in2,in3,in4,s0,s1);
input in1,in2,in3,in4,s0,s1;
output out;
wire s0_n,s1_n,w,x,y,z;
not (s0_n,s0),(s1_n,s1);
and (w,in1,s0_n,s1_n),(x,in2,s0_n,s1),
    (y,in3,s0,s1_n),(z,in4,s0,s1);
or (out,w,x,y,z);
endmodule
